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SUSTAINABLE REDEVELOPMENT WITH A CLOSED MASS BALANCE
In Canada a lot of former industrial sites are scheduled to be redeveloped as residential and community areas: most brownfield sites are located in densely populated areas. How to deal with contaminated soils is often a challenge. The relation of densely populated areas and contaminated land creates a need for sustainable redevelopment of these sites, including the use of large volumes of sand for backfilling and grading purposes.
There is a need for an affordable and sustainable technique for cleaning these sites. Techniques like biological treatment (attenuation), "pump and treat" and soil washing are alternative ways for sustainable redevelopment of these sites.
Treatment of the soils in a soil washing plant and reusing the processed material is one option. Soil washing has different benefits for brownfield development projects.
Soil washing technique
Soil washing facilities are designed for a water-based volume reduction process, using particle size and density separation. The cleaning technique is based on the principle that contamination most affects the fine (organic) particles in the soil. A traditional soil washing process has three major stages: Coarse material separation (more than 2 mm), sand separation (2 mm-63 pm) and dewatering of the fines (less than 63 pm).
After sampling and physical and/or chemical analysis, the coarse material and the sand is potentially...